Poor Medea. Always vilified and accused, now the poor woman has been subject to two brutal theatrical assaults in as many weeks. First was the woeful Medea/Medea at the Gate in London, and now this curious effort, performed in a giant paddling pool. For no discernible reason, you take off your shoes and socks and watch the action with your feet dipped in the cold water, while children's soft toys float by. It appears Medea's poor murdered babes were keen on Pokémon and Winnie the Pooh.

It is all quite atmospheric, and it has a hypnotic intensity as Medea – in a wheelchair – and her maid confront each other in the watery gloom, though exactly what they are accusing each other of is impenetrable, as if they are talking in code. I understood each individual word, but few complete sentences.

Nonetheless, there are some good things here, from the white children's clothing that flutters on a washing line outside the theatre entrance, to the extraordinary singing and chanting that creates a strong sense of ritual and timelessness as the chorus wade across the pool and the shadows dance.

But if you were unfamiliar with the Medea myth, you would be none the wiser after seeing this. The piece is so remote, so hermetically sealed and internalised that it starts to feel as if director and cast are exploring a private obsession they don't want to share. A great design idea is not enough to keep the attention, even in a show that lasts less than an hour. Poor, poor Medea: she deserves better than this damp squib.